Cellular mobile radio networks like GSM, UMTS, LTE, cdma2000 include a multitude of radio cells. A radio cell is the geographic area of the cellular mobile network in which the radio signal transmitted by a base station can be received. Generally two types of radio cells can be distinguished: Macro cells and Femto cells.
Macro cells achieve a radius of several hundred meters or more and usually serve both outdoor and indoor locations with open access to any subscriber registered to the cellular network. Macro base stations are typically owned, installed and operated by the Mobile Network Operators.
Femto cells usually serve indoor locations and cover smaller areas compared to the macro cells, such as in trains, aircrafts, ferries and building, like offices, private houses, shopping malls, train stations, airports and the like. Femto base stations are installed on the mobile radio customers' premises and can be owned by the customers. Access to a femto cell is typically under control of its owner and will be restricted usually to a small group of subscribers. Femto cells operating without user access limitation are also referred to as pico cells. An example of a Femto cell is disclosed in US Patent Publication No. 2009/0092122 A1.
In all radio cells of a cellular network, a set of common channels is broadcast by the base station. These common channels include e.g. synchronization channel, pilot channel, broadcast channel and paging channel. Depending on the specific radio technology further common channels may exist, but the mentioned channels are typical for each on the mentioned cellular radio systems.